The management of central Vietnam's biggest hydropower plant has been unable to explain several irregularities at a dam that is currently leaking, while several minor earthquakes have been detected in the area.
At a meeting with Quang Nam Province National Assembly representatives on April 18, Tran Van Hai, director of Hydropower Plant Management Unit 3, which manages the Song Tranh 2 plant, said the water level at the reservoir was 155-meter high and water was leaking at 75 liters per second.
But he was unable to answer Dang Phong, Chairman of Bac Tra My District People's Committee, who asked why the leakage volume was only 30-liter per second when water level was higher several weeks before.
Another unanswered question raised by many officials who inspected the leaking dam on April 18 was why the leak through a slit between concrete blocks has become worse when such slits are supposed to become narrower in hot weather.
At the meeting, Hai said the plant would apply Chinese technology to widen the slits via drilling and pump Polyurethane inside to clog the hole. He said the method has been used successfully at the Three Georges Dam in China.
Meanwhile, local authorities said there was a minor earthquake in the area at around 8 p.m. on April 15, and an aftershock at 4 a.m. the next day, forcing many residents in Tra Doc Commune, Bac Tra My District, to run from their homes.
The Quang Nam People's Committee has asked the Ministry of Science and Technology to install a new earthquake detection station in Bac Tra My District and study earthquake risks in the area.
Hai said there have been 80 minor earthquakes in the area, including 40 before construction of the dam began in 2006. There have been between 5 and 7 minor quakes since April 7, he said.
Tran Anh Tuan, deputy chairman of Bac Tra My District People's Committee, said experts at the Institute of Geophysics said the equipment for detecting earthquakes at the Song Tranh 2 Hydropower plant was ineffective.